Let's draw the situation.
Based on the sum of segments property, we can define the following equation.
[tex]AC=AB+BC[/tex]Replacing the given expressions, we have
[tex]19=3x+6x+1[/tex]Let's solve for x
[tex]\begin{gathered} 19-1=9x \\ 9x=18 \\ x=\frac{18}{9} \\ x=2 \end{gathered}[/tex]We use this value to find BC.
[tex]BC=6x+1=6(2)+1=12+1=13[/tex]